Reactor



2 Sheets-Sheet l REACTOR H. C. FORBES Filed June ll, 1927 Dec. 26, 1933.

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REAGTOR Filed June 11, 1927 2 Sheets-Sheet 2 INVENTOR W5/farmi I I/ BY IATTORNEY Patented Dee.` ze, 1933 1,940,854

UNlTEnsTATEs PATENT orales t nsllc'ron f Henry C. Forbes, Pittsburgh, Pa., assignor to Westinghouse Electric & Manufacturing Colnpany, a corporation of Pennsylvania,

Application June 11, 1921; serial No. 193,153

'l clama. (cl. 17a-41.5).

My invention relates to reactors, and it has been assembled on a single shaft, and arranged particular relation to variable condensers such in operative relation to the corresponding stators. i as are commonly utilized in radio receiving and Such condensers are known in the art as gang" transmitting equipment. condensers, and are usually so constructed that One object of my invention is to provide a the rotor and the frame may be grounded in o0 variable condenser that is extremely rigid in order to minimize the capacity eiIect oi the operf construction. ators hand.

Another object ofmy invention isto provide A kgang condenserk constructed according to a variable condenser that is substantially unthe teaching of the prior art, provided with end l0 affected by therough handling to which an asplates held together bya plurality o! tie-rods, o6

Vsembled radio set is subjected during shipment. does not permanently remain in adjustment.

Another object of my invention is to provide Torslonal and other stresses tend to destroy the a frame, or support, for a gang condenser, that parallelism of the end plates, and, consequently, is, alcondenser having more than onefvariable the correct spacing between rotor and stator component connected to the same shaft, which plates cannot be maintained when the device is 70 will remain. rigid under .all conditions of hansubjected torough usage.

v dling, shipment and usage. f I have accordingly, by the present invention,

Another object of my invention is to provide done away with the end-plate and tie-rod cona condenser-supporting.frame that will be `free, struction, and yhave provided a one-,piece confrom unbalanced vstresses when complete, and denser Iramethat is substantiallyunafiected by 75 which consequently `will not tend to distort durusage of the roughest sort. Specifically. my inlng long continued use. vention contemplates replacing the customary Another object of my invention is to provide a end-plates and tie-rods by an unitary supporting condenser-supporting frame that may be cheaply tllrllelrlt` shaped Somewhat like beth-tub, be-

manufactured, and one that requires only a few tween the end portions of which the rotor is 80 machining operations, i mounted, and along the sides of which are car- Another and more specific object of my invenried a plurality of` insulating strips adapted to tion is to provide an improved form of statorsupport the stator plates. plate assembly particularlyl suitable for use in a Among the novel features oi my invention are i condenser of the type referred to above. l those particularly Set forth 1u the appended 85 By far the greatest number of variable conclaims. The inventionin its generic aspect, howdensers utilized in radio transmitting and receivever, as well as further objects and advantages ing sets at the present time comprise a plurality thereof, will best be understood by reference to of stationary plates, known as the fstator, and vthe OllOWnS description 0f B SlJeClllC embodia plurality of movable plates, known as the ment, taken in connection with the accompany- '90 rotor. The rotor is usually mounted on a shaft ing drawings, in which: extending through bearings carried by end plates, Figure 1 is a top plan view o! a preferred em- -the engi plates being held together by a plurality bodiment of my invention; of \merallic tie-rods. In condensers of the low- Fig. 2 is a view in elevation; t

loss? type, suchas disclosed on page 119 or the Fig. 3 is an end elevational View, illustrating a 9i 1918lediuon or Bureau of standards circular No. preferred form of actuating means: '14, the end plates are metallic, andthe stetor- Fis. 4 is a Cross-Sectional view taken alone e plates are supported thereiromvby a plurality oi line COIIGSDOHCI'HIB t0 the line. IV-IV 0f F18. 2,

, insulating elements, preferably of quartz or the l00kil1g toward the left;

like. In other, and earlier, `condensers the end Fig. 5 iS a View of a Single condenser plete 100 plates were constructed of a material such'as Fig. 6 iS an end elevational view of a statorbakelite, and the ystator plates were supported plate assembly, illustrating the marmer in which therefrom by the tie-rods themselves, insulation Such assembly is held together by plurality Of between the rotor and stator being provided by spacer elements; y

- the end plates. Fig. l is a plan view of a stator-plate assembly, 105

With the advent of radio receiving sets employpartly in section; f Y ing a plurality of tuned circuits, it has become F18. 8 is a sectional view taken $10118 line desirable to adjust the frequency of all of, such corresponding to the line IV-IV oi Fig. 6; i circuits by a single control device, and to this Fiss. 9 and l0 are views o! alternative forms 5D end the rotors or two or morecondensers have spacer-elements. 110

Referring specifically to Figs. 1, 2 and 4, my irnproved condenser comprises a one-piece metallic structure 1 which is shaped somewhat like a bath tub, having end portions 2 and 3, side portions 4 and 5 and a bottom portion 6. The side portions 4 and 5 are each cut away intermediate the ends to below the level of the tops of the said ends, leaving a plurality of upstanding ears 7.

Insulating strips 8 are aflixed by means of rivets 10 to the upstanding ears 7 and to the end portions 2 and 3, and extend parallel to the long axis of the structure.

A plurality of groups of stator-assemblies 11 are suspended between and supported by the insulating strips 10 by means of a plurality of small bolts 12 or analogous devices.

Each of the stator-assemblies is provided with a soldering lug 13 which is maintained in electrical Contact with the stator plates by means of one of the bolts 12.

The end portion 2 of the frame is provided with an opening through which extends one end of a shaft 14 carrying a plurality of groups 15 of rotor plates, eachplate being mounted in a circumferentiallymilled groove.

The end portion 3 of the frame 1 is provided With an opening sufficiently large to accommodate a threaded bushing 16 which has `an axial opening therethrough of a diameter just suiciently large to accommodate the shaft 14. The bushing 16 is held in position by a nut 17, and a lock-nut 18. A collar 20 is mounted on the shaft adjacent the lock-nut 18, and is held in position by means 0f a pin 21. A spring-washer 22 encircles the shaft between the collar 20 and the lock-nut 18, and exerts a thrust on the shaft tending to move it toward the end portion 2.

Movement of the shaft under the influence of the spring-washer 22 is prevented by the hub 23 0f an operating wheel 24, which is mounted on the end of the shaft extending beyond the bushing 16 and is held in pla'ce by a pin 25.

The manner in which the operating wheel 24 is actuated will be more clearly apparent from an inspection of Fig. 3, to which reference should now be made.

The wheel 24 comprises the hub 23, a rim portion 26 on which station call letters, or frequency indicia may be affixed, and two grooved rim portions 27 and 28 having the same diameter, and both being of less diameter than the rim portion 26.

A cord, or cable 30 passes successively around the grooved rim portions 27 and 28, the ends of the cord being wrapped around screw-threaded elements 31 and 32, respectively.

The screw-threaded elements 31 and 32 are carrled on opposite ends of a short shaft 33, being held in place thereon by pins 34 and 35, to which the otherwise free ends of the cable 30 may be aixed.

The shaft 33 is mounted in openings provided in bent-out ear portions 36 and 37, which portions are integral with a depending plate 38 that is affixed to the end 3 of the frame by a plurality of bolts or rivets 40.

The upper end of the plate 38 is provided with an additional bent-out lug 41 which is covered with rubber. and cooperates with lugs 42 and 43 carried by the operating wheel to limit the rotation of the wheel in either direction.

A small knob, or dial 44, may be affixed to the end of the shaft 34 adjacent the point where the said shaft extends through an opening in a radioset panel 45.

A slack-adjusting device, comprising a small plate 46 and a screw 47, is carried by the operating wheel, and serves to prevent the cord 30 from slipping in the grooved rims 27 and 28.

Rotary motion given to the dial 44 causes the cord 30 to wind up on one of the screw-threaded elements, and to unwind at an equivalent rate from the other screw-threaded element. The cord, inasmuch as it is prevented from slipping in the grooved rims, transmits motion to the operating Wheel and causes angular motion of the rotor plates with reference to the stator plates.

Inasmuch as the underlying purpose of my invention is to provide a condenser which is more rigid than condensers of the prior art, it is necessary that the individual stator plate assemblies themselves be extremely rigid.

Referring to Fig. 5, each individual stator plate is provided with a plurality of integral lugs 50, 51 and 52. The plates are assembled in spaced relation, as shown in Fig. 3, and are held in position by a plurality of spacer elements 53, 54, and 55 having openings through which extend the lugs on each plate.

The spacer elements 53 and 55 are constructed as shown in Fig. 9, and preferably comprise a flat strip 56 in which has been embossed a cupshaped depression 57 through the bottom of which a plurality of openings 58 are formed, the said openings being equally spaced apart and of a size just sufficiently large to accommodate the lugs 50 or 52 on the individual plates. The edges 60 of the spacer elements are turned down, giving these elements a U-shape cross-section, and the ends thereof are provided with openings 61 and 62v to accommodate the mounting screws l2.

The bottom spacer element 54 may be constructed as a plain flat strip having equally spaced openings therethrough, as `shown in Fig. 10.

In the assembly of each stator plate group the requisite number of plates is held rmly in a jig which spaces them the desired distance apart. The spacer elements 53, 54, and 55 are then slipped over the lugs and a cord may be Wrapped around the said elements between the condenser plates in order to hold them temporarily in position.

Melted solder is then allowed to ll the cupshaped depressions of the spacer elements 53 and 55 successively, which, when it solidies, unites the plates and the spacer elements into a rm, rigid structure.

The bottom spacer element is then soldered to the plates in an analogous manner, a lesser amount of solder being necessary. It is, of course, feasible, though not necessary, to utilize three spacer elements of the same character as the elements 53 and 55.

After the soldering operation is completed, the cord may be removed, or, if the plates have remained in the jig during the operation, they may be then taken from the jig with full assurance that the predetermined spacing will not later vary.

In order that rough handling shall not cause injury to the stator or rotor groups after assembly, I have made the end plates of each group of material much thicker than the material utilized for the intermediate plates.

In the modification of my invention shown in the drawings, the insulating strips 8 are illustrated as extending from one end of the condenser frame to the other. Although this method of construction is preferable, it is not absolutely necessary, inasmuch as the strips themselves add loo lid

substantially nothing to the rigidity of the frame. Itis, accordingly, feasible' to replace the continuous strip by a plurality of short sections supported from the upstanding ear portions of the framesides and from the end portions thereof. This modification, being believed obvious, is not illustrated.

I am aware of the fact that it has previously been proposed to Iconstruct a condenser having metallic end pieces from which the stator plates are supported on insulating elements. Such a condenser is shown on page 1,9 and opposite page 318.0f the l1918 editionof circular #74 of the Bureau of Standards. 'The condenser shown in that publication, however, was not rigid. would be impossible to construct a modern gang condenser in the manner illustrated. I have also found that if such a gang condenser is constructed in the ordinary way by utilizing a plurality of end elements bolted together by spacer devices, itisl very easily disarranged by torsional stresses. v

My improved condenser is extremely rigid. After having once been assembled and adjusted, the original spacing between the stator4 and rotor plates does not appreciably change, no matter how roughly the device may be handled. The spacing betweenv the plates is also not appreciably affected by atmospheric changes, any elongation of the supporting frame being followed by mcvement of they rotor carrying shaft, since the shaft is free to move in oneend of the frame but is not free to move with reference to the other end.

The supporting frame may either be die cast or may be drawn from a flat sheet of deep-drawing steel in one operation, and after drawing, the frame may be trimmed in a second operation and is then ready for punching in accordance with the requirements of the design.

In some respects the drawn frame is more desirable than one which has been die cast. Die casting introduces certain strains which are likely to later be relieved by the punching and boring operations, and cause a certain amount of distortion. The die casting is inherently expensive and must be carefully controlled, in order to avoid warping and crystalline growth which combine to cause distortion.

For these reasons, I have found it preferab to draw the frame, as above mentioned, although I consider either a drawn frame or a die cast frame ascoming within the scope of my invention.

Although I have shown only a single specific embodiment of my invention, I am aware that many modifications thereof are possible. My invention is, therefore, not to be limited except insofar as is necessitated by the prior art and by the spirit of the appended claims.

I claim as my invention:

l. In a variable condenser, a unitarymetallic frame having substantially parallel end elements and substantially parallel sides, insulating ele-y ments carried by said sides, and a plurality oi.' stator plates supported between said insulating elements, those portions of said frame adjacent said stator plates being cut away to reduce the capacity between said frame and plates.

2. In a variable condenser, a box-like unitary metallic supporting structure having substantially parallel ends and substantially parallel sides, insulating elements carried by said sides a plurality of groups of stator plates suspended between said insulating elements interiorly of said metallic structure, and a shaft carrying a plurality of rotor elements journalled in said end elements, the sides of said metallic structure being cut away adjacent the points where said stator plates `are afiixed to said insulating elements.

3. In a variable condenser, a box-like unitary metallic supporting structure having substantially parallel ends and substantially parallely sides`, insulating elements carried by said sides, a plurality of groups of stator plates ailixed to and carried between said insulating elements, the afiixing means for said stator plates also constituting an electrical and mechanical connection between the said plates, and a shaft carrying a plurality of groups of rotor plates journaled in said ends.

4. In a variable condenser, a unitary troughshape metallic supporting frame having end walls and side walls, insulating elements carried byv said side walls, a plurality of stator plates suspended between said insulating elements interiorly of said frame, and a shaft carrying cocecrating rotor plates journaled in said end walls.

5t. As an article of manufacture, a trough-shape metallic condenser-element supporting frame having integral side, end and bottom portions, the side portions being so modified as to permit the mounting thereon of insulating elements adapted to support condenser-stator-plates.

` 6. AA variable electric condenser comprising a unitary, jointless wrought metallic shell withv srnooth, vrounded wall-connecting edges and corners and integral bottom, side and end walls, a set of stator plates and a set of rotor plates contained within the shell and supported thereby, one of said sets of plates being in electrical connection with said shell.

'7. A variable electric condenser comprising a unitary, jointless wrought metallic shell with smooth, rounded wall-connecting edges and corners, and integral bottom,I side and end walls, one of said walls having an opening therein, a stator unit in said shell comprising a set of stator plates, an insulating memberon the exterior of said shell over said opening, a connecting clement securing said stator plates to said insulating member, and a rotor unit in said shell comprising a rotor shaft journaled in said end walls and a set of rotor plates on said shaft, the rotor unit being in electrical connection with the shell.

HENRY C. FORBES. 

